[quagga-users 14842] MININET - first steps

Hello,
I'm trying to use Quagga with mininet (Ubuntu 14.04). I have a certain 
topology and I'd like to run OSPF on all of them to capture routing 
packets.
What's the correct flow of operations?

I tried to launch zebra daemon on every router, than ospfd but after the 
first one I get the following error:

ospfd -i=./quagga/ospf.pid

Can't create pid lock file ./quagga/ospf.pid, no such file or directory

I have given permission to the quagga user for that folder and also 
tried to manually create the file.